An apparatus and method for creating enlarged particles in a flow. The apparatus includes a coiled tube having a tube diameter and a coil diameter, the tube having an input receiving the flow and an output, the tube having a length between the input and the output. A heater heats a first portion of the tube along a first, longitudinal portion of the tube, and a cooler cools a second, longitudinal portion of the tube along at least a second portion of the tube. The method includes heating a first portion of the tube along a first longitudinal portion of the tube, and simultaneously cooling a second portion of the tube along at least a second longitudinal portion of the tube. While heating and cooling, the method includes introducing a flow into an interior of the tube at an input, the flow moving the output.

An apparatus and method for condensationally enlarging particles in a flow of air or other gas. The apparatus includes a coiled tube having a tube diameter and a coil diameter, the tube having an input receiving the flow and an output, the tube having a length between the input and the output. The walls of the tube are wetted with a condensing fluid. The walls of the first portion of the coiled tube are held a temperature that is lower than the highest temperature in the second portion of the tube. The tube may have a third vapor recovery portion with wall temperature lower than the highest temperature in the second portion, and which optionally may not be coiled. While heating and cooling, the method includes introducing a flow into an interior of the tube at an input, the flow moving the output.

An approach for counting particles suspended in a flow of gas or liquid in instruments that direct the flow through an illuminated region. Pulses are detected when the signal is below a threshold amplitude and moves above the threshold amplitude. This movement above the threshold creates a dead time during which only one pulse is detected until the signal amplitude moves sufficiently below the threshold such that a subsequent particle creates a distinct pulse. After counting the number of pulses, and determining the measured live time that the signal is below the threshold value, an initial particle concentration is calculated, and the calculation corrected for coincidence by calculating an actual live time as a measured live time minus a constant multiplied by the number of distinctly counted pulses, where the constant has the units of time. From this, particle concentrations in a volume can be determined.

Various embodiments include methods and systems to dilute a sampled particle-laden aerosol stream in a recirculating type of aerosol diluter system. In one embodiment, a system to dilute a sampled aerosol stream includes an aerosol sample inlet. A primary diluter device includes a first inlet to receive the aerosol stream and a second inlet to receive a filtered portion of the aerosol stream and combining the filtered portion with an additional sampled aerosol stream. A flow diverter device splits at least the sampled aerosol stream into a first portion of the sampled aerosol stream and a remaining portion of the sampled aerosol stream. A filter receives the remaining portion of the sampled aerosol stream and provides a filtered aerosol stream to the second inlet of the primary diluter device. Other methods and apparatuses are disclosed.

Apparatuses for increasing the effective size of gas-entrained particles in a particle detector are disclosed. In one embodiment, an apparatus comprises an evaporation chamber, a condenser in fluid communication with the evaporation chamber, and an inlet in fluid communication with the condenser for receiving a stream of sample gas containing gas-entrained particles. The evaporation chamber includes a heating element and a porous support surrounding the heating element. The porous support carries thereon a working fluid, and the heating element vaporizes the working fluid to form vapor within the evaporation chamber. The porous support may include a portion which extends into a working fluid reservoir.

A particle counting method comprises obtaining first particle information related to the gas to be measured by a first particle counter with a first particle size detection range, obtaining second particle information related to the gas to be measured by a second particle counter with a second particle size detection range, and generating particle size distribution information according to the first and second particle information. The first particle information includes a plurality of particle size ranges and a plurality of particle quantities wherein each of the plurality of particle size ranges corresponds to a respective one of the plurality of particle quantities, the second particle information includes the quantity of particles of which the size values are in the second particle size range, and the lower limit of the second particle size range is lower than that of the first particle size range.

A condensation particle counter includes a saturation section, an aerosol inlet assigned to the saturation section, a condensation section, a measuring section for condensation particles, and an outlet section. The aerosol inlet allows a flow of an aerosol loaded with particles. Each of the condensation section, the measuring section and the outlet section are arranged downstream of the saturation section. A critical nozzle is arranged in the outlet section. The critical nozzle includes a critical nozzle inlet. A pump suctions the aerosol. An outlet line extends from the critical nozzle to the pump. A valve device is arranged in the outlet line between the critical nozzle and the pump. A pressure measuring device is arranged upstream of the critical nozzle inlet. The outlet line is entirely closed or partially closed by the valve device depending on a measurement value of the pressure measuring device.

A method and apparatus for evaluating the chemical composition of airborne particles by sequentially collecting and analyzing airborne particles in-situ. The method includes: collecting particles; enlarging the particles through water condensation; accelerating the enlarged particles onto a surface to collect enlarged particles; and analyzing the enlarged particles by: isolating the surface; passing a carrier gas over the surface; heating the surface to thermally desorb collected particles into the carrier gas; transporting this evolved vapor into detectors; and assaying the evolved vapor as a function of a desorption temperature. The apparatus includes: a sample flow inlet; a condensational growth tube; a collection and thermal desorption (CTD) cell; a carrier gas source; a heater coupled to the CTD; one or more gas detectors; and a controller configured to operate valves, the heater, the growth tube, and the CTD cell in at least an in-situ sequential collection mode and analysis mode.

Various embodiments include methods and apparatuses to reduce false-particle counts in a water-based condensation particle counter (CPC). In one embodiment, a cleanroom CPC has three parallel growth tube assemblies. A detector is coupled to an outlet of each of the three parallel growth tube assemblies, and is used to compare the particle concentrations measured from each of the three growth tube assemblies. An algorithm compares the counts from the three detectors and determines when the particles counted are real and when they are false counts. Any real particle event shows up in all three detectors, while false counts will only be detected by one detector. Statistics are used to determine at which particle count levels the measured counts are considered to be real versus false. Other methods and apparatuses are disclosed.

A particle counting device includes a scanner probe having a first opening for receiving particles from a sample surface and second openings. Pumps produce a first airstream flowing from the first opening and a second airstream flowing to the second openings. A flow device splits the first airstream into third and fourth airstreams. A first particle detector detects particles in the third airstream. The first particle detector is capable of detecting particles within a first range of particle sizes. A second particle detector detects particles in the fourth airstream. The second particle detector is capable of detecting particles within a second range of particle sizes different from the first range of particle sizes. Control circuitry controls the flow device and the pumps to provide a first flow rate of the third airstream and a second flow rate of the fourth airstream that is larger than the first flow rate.